At least 30 people were killed in attacks in Paris, France and a hostage situation was under way at a concert hall in the French capital, French media reported on Friday.

Several explosions were heard near a stadium where a friendly France-Germany soccer match was being held, attended by President Francois Hollande.

Police helicopters circled the stadium north of Paris as Hollande rushed back to the interior ministry to deal with the situation.

Police confirmed there had been shootings and explosions at the stadium, but not the number of casualties.

Witnesses said police closed down a neighborhood in central Paris where media said gunmen had fired in a restaurant, causing multiple casualties.

"I was on my way to my sister's when I heard shots being fired. Then I saw three people dead on the ground, I know they were dead because they were being wrapped up in plastic bags," student Fabien Baron told Reuters.